The invention relates to improved refrigeration systems that have a housing for an evaporator which is equipped with a defrosting mechanism and adapted for mounting on an exterior wall of a refrigerator compartment.
Refrigerating systems having a detachable unit for installation in an opening in the side of a refrigerator are known. Such a system, as shown in U.S. Pat. No. 2,525,868, is relatively complex and expensive to manufacture. Its design requires two main sections, a body section within which the evaporator is mounted, and a frame section which is mounted within the opening in the sidewall of the refrigerator. This frame section is provided, in one embodiment, with shutters which are located in the ports of the refrigerator chambers wall within the frame section, and in another embodiment with shutters in the frame section as well as in the body section. During a defrost cycle such shutters are closed allowing the circulation of warm air from the outside to defrost its enclosed cooling unit. However utilization of such type of shutters is relatively thermally inefficient as well as being more complex in design and therefore more expensive to manufacture. Furthermore, in order to initiate a defrost cycle a single inspection door, which constitutes an exterior port, must be manually opened; also since this single port functions simultaneously as a warm air intake inlet and as an air discharge outlet, its thermal efficiency is reduced. Among its other disadvantages, such a system, not having a preformed, unitary main body section, is relatively more expensive to manufacture.
Refrigerator systems with a mechanism for defrosting a cooling unit located within the refrigerator compartment which utilizes ambient air are known. Such systems are not adapted to be utilized outside of said refrigerator chamber nor are they as simple and inexpensive to manufacture nor do they provide as efficient and relatively quick defrosting as compared to the unit embodying the present invention.
A refrigerator system with a mechanism for defrosting an evaporator coil located within a separate compartment which is integral with a refrigerator cabinet having another separate compartment used to store pershiables and which utilizes ambient air to defrost said evaporator is shown in U.S. Pat. No. 2,214,268. Among its several disadvantages is that it is not adaptable to be separately mounted on the storage compartment, it does not include a preformed unitary body section, and it is not adaptable to utilize slide-in components. Furthermore such a system is more expensive to manufacture, and its overall design is not as efficient in defrosting the evaporator coil located therein, all of which are primarily due to the totally different design approach used and implementation thereof.